CentOS7にcudaを入れると、Xが立ち上がらなくなります。
cudaのインストールまでは成功します。

原因と対処法をご存知の方、ご教授お願いします。

環境
OS: CentOS Linux release 7.5.1804 (Core)
CPU: Intel i5 2.8GHz (8th gen)
GPU: NVIDIA Geforce 1070
GPUのドライバ: nouveauではなく、NDIVIAのものを使用
cuda 10(本来はver.9を入れたい)

追記

Knoppixを使って、/var/log/Xorg.0.log を取ることが出来ました。
コンソールからstart x を実行しています。
以下の通り、Segmentation fault が発生しています。

[    41.821] (II) Loading sub module "fb"
[    41.821] (II) LoadModule: "fb"
[    41.845] (II) Loading /usr/lib64/xorg/modules/libfb.so
[    41.858] (II) Module fb: vendor="X.Org Foundation"
[    41.858]    compiled for 1.19.5, module version = 1.0.0
[    41.858]    ABI class: X.Org ANSI C Emulation, version 0.4
[    41.858] (II) Loading sub module "wfb"
[    41.858] (II) LoadModule: "wfb"
[    41.859] (II) Loading /usr/lib64/xorg/modules/libwfb.so
[    41.864] (II) Module wfb: vendor="X.Org Foundation"
[    41.864]    compiled for 1.19.5, module version = 1.0.0
[    41.864]    ABI class: X.Org ANSI C Emulation, version 0.4
[    41.864] (II) Loading sub module "ramdac"
[    41.864] (II) LoadModule: "ramdac"
[    41.864] (II) Module "ramdac" already built-in
[    41.880] (**) NVIDIA(0): Depth 24, (--) framebuffer bpp 32
[    41.880] (==) NVIDIA(0): RGB weight 888
[    41.880] (==) NVIDIA(0): Default visual is TrueColor
[    41.880] (==) NVIDIA(0): Using gamma correction (1.0, 1.0, 1.0)
[    41.881] (**) NVIDIA(0): Enabling 2D acceleration
[    41.899] (EE) 
[    41.899] (EE) Backtrace:
[    41.899] (EE) 0: /usr/bin/X (xorg_backtrace+0x55) [0x56458cd0a135]
[    41.899] (EE) 1: /usr/bin/X (0x56458cb5c000+0x1b1ec9) [0x56458cd0dec9]
[    41.899] (EE) 2: /lib64/libpthread.so.0 (0x7f1d21e19000+0xf6d0) [0x7f1d21e286d0]
[    41.899] (EE) 
[    41.899] (EE) Segmentation fault at address 0x0
[    41.899] (EE) 
Fatal server error:
[    41.899] (EE) Caught signal 11 (Segmentation fault). Server aborting
[    41.899] (EE) 
[    41.899] (EE) 
Please consult the The X.Org Foundation support 
     at http://wiki.x.org
 for help. 
[    41.899] (EE) Please also check the log file at "/var/log/Xorg.0.log" for additional information.
[    41.899] (EE) 
[    41.900] (EE) Server terminated with error (1). Closing log file.